4.4 Using Guile Interactively

When you start up Guile by typing just guile, without a
-c argument or the name of a script to execute, you get an
interactive interpreter where you can enter Scheme expressions, and
Guile will evaluate them and print the results for you. Here are some
simple examples.

This mode of use is called a REPL, which is short for
“Read-Eval-Print Loop”, because the Guile interpreter first reads the
expression that you have typed, then evaluates it, and then prints the
result.

The prompt shows you what language and module you are in. In this case, the
current language is scheme, and the current module is
(guile-user). See Other Languages, for more information on Guile’s
support for languages other than Scheme.